Condenser adjusting device



. March 8, 1950 R. N. GANGEL 2,501,671

CONDENSER ADJUSTING DEVICE Filed Jan. 7, 1946 8 INVENTOR 20 ROBERT NEILCANCEL ATTORNEY Patented Mar. 28, 1950 UNITED STATES PATENT OFFICECONDENSER .mwsrmc navrcn Robert Neil Gangel, Oceanside, N. Y.

Application January 7, 1946, Serial No. 639,678 2 Claims. (Cl. 115-415)(Granted under the act of March 3, 1883, al amended April 30, 1928; 3700. G. 757) This invention relates to condensers of the variable airdielectric type and more particularly to an adjusting device for theplates thereof.

The outer plates of tuning condensers such as are used in radioreceivers and the like are generally provided with a series of radiallyextending slots that form substantially oriented sections which may beindividually bent away from or toward the next adjacent plate to varythe capacity of the condenser. This adjustment is known as a trackingadjustment. One example of the necessity for such tracking adjustmen iswhere it is desired in a radio receiver, to simultaneously tune theradio frequency and local oscillator stages in order to produce anintermediate frequency for further amplification. Here, due to theirregularities in the capacity change between stages in a gangedarrangement, it is often necessary to bend the slotted sections on theouter plates of each gang a small amount to vary the capacity of thegang" slightly at that point in the condenser rotation.

Heretofore, this critical adjustment has been made by using a pair ofpliers to bend the plates to what was estimated to be the desiredamount. By repeated bending operations and trial and error method, thedesired result was finally achieved. This manner of obtaining theadjustment is manifestly unsatisfactory for obtaining eflicient, direct,and precise adjustment. In addition, this method is fraught with thehazard of causing adjacent, unslotted plates of the condenser to becomedisaligned by contact with the nose of the pliers.

Accordingly, it is an object of the present in- 5 vention to provide anadjusting device for permitting this tracking adjustment to be made tothe plate of a condenser in a smooth, accurate and eflicient manner andwithout danger of damage to the adjoining plate of the condenser.

Another object of the invention is to provide a device of this characterwhich is simple in design and construction, inexpensively manufacturedand reliably operative in making minute changes in the capacitance ofcondensers.

With the above and other objects and features in view, the inventionwill now be described with reference to the accompanying drawings whichillustrate a preferred embodiment of the invention and will be pointedout in the claims.

In the drawings:

Fig. 1 is an end elevation of the outer plate of the rotor of a variablecondenser illustrating the improved adjusting device mounted thereon;

Fig. 2 is a detailed sectional elevation men along the line II-II ofFig. 1; and

Fig. 3 is a detailed sectional elevation of one of the adjusting screwunits. said section being taken along the line 1III1I of Fig. 1.

Referring to Fig. 1 there is shown the outer plate In of a variable airdielectric condenser mounted on the conventional rotor shaft II. Theouter plates Ill (Fig. 2) are provided with radially extending slots Hto form substantially oriented sections I that may be individuallyflexed either toward or away from the adjacent plates it of thecondenser to vary the capacitance of the latter. As previously stated.it has been the practice heretofore, to bend the sections it by using apair of pliers. It will be readily seen from reference to Fig. 2 thatthe insertion of even long nose pliers between the delicately mountedplates I8 and It is likely to cause misalignment of the adjoining plateIt by contact of the pliers therewith.

To overcome these difficulties, the present invention provides anindependent, individual adjustment for each of the sections it. Eachadjusting means comprises a pair of oppositely disposed angular lugs orprojections 20 secured as by riveting or welding as at 22 to the outsideof the outer plates III. The lugs 20 for each section are arranged inspaced relation and in alignment with each other. If desired, the lugsmay be struck from the metal of the condenser plate III althoughpreferably it is believed to be more satisfactory to mount the lugs onthe plates as shown.

A headed adjusting screw 24 passes through an opening 26 in the upperlug III with clearance and the shank of the screw is threaded into anopening 28 provided in the lower lug. Means for preventing anysubstantial longitudinal movement of the screw with respect to the upperlug 20 is provided by a nut 30 which is threaded on the shank to aposition where just sumcient clearance is provided between theundersurface of the lug and the upper surface of the nut to provide forfree rotation of the screw II. The nut is secured in this position byeither jamming it upon the threads of the screw or soldering the nutthereto as indicated at 32. In this manner the screw is rotatablymounted in the upper lug but anchored therein against longitudinalmovement.

In operation, by inserting a screw driver in the slot of the screw androtating the screw in one direction its section It is caused to bendslightly at a point approximately indicated by aso1,e11

3 the arrow 84, thereby flexing the section II away from the nextadjacent plate ll. Upon rotation oi the screw in an opposite direction,as the nut ll engages the undersuri'ace of the upper lug 20 the sectionII is caused to iiex in an opposite direction at the point 34, or,toward the next adjacent plate II. In this manner any one of thesections it may be positively flexed in the proper direction toprecisely the desired amount,

with a very high degree of accuracy, and without the possibility of damaing the adjacent plates. Hence. tracking adjustments may be simply andreadily accomplished with maximum ease and with assurance to theoperator of Positive control over the degree of adjustment being made.

The invention described herein may be manui'actured and used by or forthe Government oi the United States of America for government purposeswithout the payment oi any royalty thereon or therefor.

Having described the invention what is claimed as novel and desired tobe protected by Letters Patent of the United States is:

1. Apparatus for adjusting the capacitance variation as a function ofrotation of a variable condenser having a plate formed with radialsegments extending from a central body portion, said apparatuscomprising, a first lug projecting normally from substantially thecenter of area of a segment. a second lug projecting normally from saidbody portion in spaced radial alignment with said first lug, and a screwrotatably anchored in said first lug and threaded in said second lug.whereby upon turning said screw in one direction said segment may bepositively flexed to one side of the plane of said body portion, andupon turning said screw in an opposite direction, said segment may bepositively flexed 4 to the other side or the plane of said body portion.

2. Apparatus for adjusting the capacitance variation as a function ofrotation of a variable condenser having a circular plate formed withradial segments extending from a central body ortion, said apparatuscomprising, a first lug projecting normally from substantially thecenteroi'areaoiasegmentandpositionedradially inward from the peripheraledge 0! said segment. as second lug projecting normally from said bodyportion in spaced radial alignment with said first lug, a headed screwconnecting said lugs, the portion of said screw adjacent its headpassing with clearance through said first lug and the shank oisaid screwbeing threaded in said second lug, and means secured to said screwadjacent said first lug for engaging said lug when the screw is rotatedin a direction opposite to that in which the head of said screw iscaused to engage said lug.

ROBERT NEIL GANGEL.

REFERENCES CITED The following references are of record in the fllc ofthis patent:

UNITED STATES PATENTS Number Name Date 1,831,590 Ferguson Nov, 10, 19312,000,686 Bailey May 7, 1935 2,052,316 Bagle Aug. 25, 1936 2,161,532Saki-en June 6, 1930 2,208,837 Eix July 23,1940

FOREIGN PATENTS Number Country Date 303,758 Great Britain Mar. 2'1, 1930378,201 Italy Jan. 30, 1940

